According to the World Health Organization, breast cancer is the second most common type of cancer and the fifth most common cause of cancer death. In view of the commonality of breast cancer, diligent individuals subject themselves to regular mammograms for the purpose of detecting an existence of breast cancer.
An ancillary benefit of having a mammogram conducted is the ability of the radiologist to determine a radiographical density of the participant's breast tissue due to the fact that there is a prognostic relationship between breast density and cancer risk. In general, it is known in the art that the radiographical density of a breast illustrated within a mammogram may vary due to differences in the amount of fat, connective tissues, and epithelial tissues that are present. For example, because fibroglandular and connective tissues (i.e. glands, ducts, and fibers) have a relatively high x-ray attenuation, fibroglandular and connective tissues may appear to be radiographically dense/light on radiographic films. By contrast, fat has a relatively low x-ray attenuation and therefore appears to be the least radiographically dense/dark, when compared to the remaining breast tissue. Because of the distinct differences in x-ray attenuation between fat and fibroglandular tissue, segmentation of fibroglandular tissue from the rest of the breast is possible.
A known breast density estimation standard may be based upon a four-category Breast Imaging Reporting and Data Systems (BI-RADS) lexicon. Upon visually assessing a mammogram, a radiologist may classify the radiographical image of the breast into one of four BI-RADS compositional categories defined as: 1: Fatty, 2: Scattered, 3: Heterogeneous, and 4: Dense. Women whose breasts are categorized in the BI-RADS 4/densest breast category are four-to-six times more likely to develop breast cancer than those categorized as BI-RADS 1/fatty
Because the above standard in breast density estimation involves a radiologist's visual assessment of a mammogram, this assessment is subjective and relies on the perception of the radiologist. While such a subjective density classification is quick to use and widely employed, it has been proven to be limited due to considerable intra- and inter-reader variability of a radiologist.
Further, as also known in the art, the use of mammography is not ideal because of the associated radiation exposure to the participant that is undergoing breast evaluation Even further, a mammogram is a two-dimensional projection which, by definition, does not provide an accurate, three-dimensional volumetric estimation of the breast density due to the tissue thickness not being taken into account. Even further, it is also known that women are apprehensive about mammography due to the uncomfortable compression of the breast associated with the scan.
Accordingly, there is a need in the art for an improved method and apparatus for determining breast density. In an embodiment, the novel method and apparatus is a non-ionizing method and apparatus. In an embodiment, the determined breast density may be utilized for assessing cancer risk.
Further, because the novel methodology yields parameters that are associated with high breast density, which, in turn, may be associated with increased breast cancer risk, it will be appreciated that data arising from the novel methodology may be utilized to assess cancer risk directly without the intermediate step of determining breast density.
Yet even further, by identifying women having high breast density, further preventative measures can be implemented.